The database quest for the Square Kilometre Array

The Square Kilometre Array Observatory (SKAO) is a next-generation radio telescope that is being built in two locations in the Karoo region of South Africa and the Murchison region of Western Australia forming one Observatory run from a global headquarters based in the United Kingdom at Jodrell Bank. At the heart of the SKA software, there will be a database that persists and replicates its metadata between these three sites that have different functions. This paper will describe the main requirements for the SKA database, how this has been done in the past at the Atacama Large Millimeter/Sub millimeter Array (ALMA) in Chile, the lessons learned there from the ten years of operations and what new options have appeared to handle the SKA, three site telescope needs. The solution needs to be highly available, performant, cost effective and easy to implement and maintain in the long term.